In the existing systems, the Enhanced-Dedicated Transport Channel (E-DCH) data frame belongs to the data frame type. It is used in the uplink direction, and is contained through high-layer signaling indicator. The E-DCH data frame is defined as two types of structures: type 1 and type 2. If it contains a media access control-enhanced sublayer protocol data unit (MAC-es PDU), then type 1 structure is used; and if it contains a media access control-improved sublayer protocol data unit (MAC-is PDU), then type 2 structure is used.
FIG. 1 is a schematic diagram of the format of the E-DCH uplink data frame in the conventional art.
As shown in FIG. 1, E-DCH data frame type 1 and type 2 contain two component parts: header and payload, with both of them containing the following several fields and the difference being that the included data units are different, as described in the above:
1. Header cyclic redundancy checksum (CRC) field:
The “CRC check code” field is the result of the CRC applied to the remaining part of the header (i.e. from bit 0 of the first byte to bit 0 (included) of the last byte of the header (not including the Header CRC Cont four bits)) with the corresponding generator polynomials. The length of the “header CRC check code” field used for an E-DCH uplink data frame is 7 bits or 11 bits. The 7 bits are bit 7 to bit 1 of the first byte of the frame header of the E-DCH data frame, and the 11 bits further contain bits from bit 7 to bit 4 of the second byte besides of the bits from bit 7 to bit 1 of the first byte;
2. Frame type indicator
The “frame type indicator” field is used to indicate whether a frame is a data frame or a control frame. The length of the “frame type indicator” field is one bit and it is located in bit 0 of the first byte of the frame header in the E-DCH data frame. The E-DCH data frame is an uplink data frame, and therefore, as described above, its “frame type indicator” field is “0”;
3. Frame sequence number (FSN)
The “frame sequence number” field represents the FSN of an E-DCH data frame, and for each transmitted E-DCH data frame, it has to generate its own FSN. If the FSN is 4 bits, then it is calculated according to the following formula: FSN=(FSN+1) modulo 16.
The range of the FSN value is 0-15. The length of the “frame sequence number” field is 4 bits and it is located from bit 3 to bit 0 of the second byte of the frame header of the E-DCH data frame;
4. Number of subframes
The “number of subframes” field indicates how many subframes are in a frame. Please note that a subframe includes a header portion and a payload portion. The value range of the “number of subframes” field is 1-16, in which, the binary code of value 1 is “0000”, and the binary code of value 16 is “1111”. The length of the “number of subframes” field is 4 bits, and it is located from bit 3 to bit 0 of the third byte of the frame header of the E-DCH data frame;
5. Connection frame number (CFN)
For E-DCH, the “connection frame number” field indicates a radio frame that the HARQ decodes data accurately. For E-DCH, this field is used for the purpose of re-ordering, and CFN (and subframe number) can be used for dynamic delay measurements. The value range is 0-255. The length of the “connection frame number” field is 8 bits and it is located from bit 7 to bit 0 of the fourth byte of the frame header of the E-DCH data frame;
6. Number of HARQ Retransmissions
The “number of HARQ retransmissions” field indicates the number of HARQ retransmissions for successfully decoding the payload, or as to the HARQ decoding failure situation, this field indicates the number of HARQ retransmissions that were used at the time when the HARQ decoding failure is detected. And the value of this field being 13 indicates that the actual retransmitted data is inappropriate to be used as the input of the outer loop power control. The value of this field being 15 indicates that the node B is incapable of calculating the number of HARQ retransmissions. The value range is 0-15. The length of the “number of HARQ retransmissions” field is 4 bits and it is located from bit 3 to bit 0 of the fifth byte of the frame header of the E-DCH data frame; the “number of HARQ retransmissions” field of the first subframe number is located from bit 6 to bit 3 of the fifth byte of the frame header of the E-DCH data frame; the “number of HARQ retransmissions” field of the second subframe number is located from bit 6 to bit 3 of the first byte of the frame header of the E-DCH data frame after the first MAC-e header. The location of the “number of HARQ retransmissions” fields of other subframe numbers in the frame header of the E-DCH data frame can be deduced in the same manner, till this subframe includes the number of HARQ retransmissions of all the MAC-es PDUs;
7. Subframe number
The “subframe number” field indicates the subframe number in which the payload is received. Except for the purpose of re-ordering, the subframe number (and control frame number) may be used as dynamic delay measurement. The value range of the “subframe number” field is 0-4 and the length is 3 bits; the first subframe number is located from the bit 2 to the bit 0 of the fifth byte of the frame header of the E-DCH data frame; the second subframe number is located from the bit 2 to the bit 0 of the first byte after the first MAC-e or MAC-i header of the frame header of the E-DCH data frame; and other subframe numbers are located from the bit 2 to the bit 0 of the first byte after the previous MAC-e or MAC-i header of the frame header of the E-DCH data frame, till all the subframe numbers are included.
8. Spare extension
The “spare extension” field indicates the location where new Information Elements (IEs) can in the future be added in a backward compatible way. The length of this field is 0-32 bytes.
9. Payload CRC
The “payload CRC” field is the CRC check of the payload. It is the result of the CRC applied to the remaining portion of the payload, that is, from the bit 7 of the first byte of the payload to the bit 0 of the payload before the payload CRC. The length is 16 bits.
The E-DCH frame protocol provides the transmission of MAC-es PDUs or MAC-is PDUs from the node B to a serving radio network controller (SRNC) by using E-DCH data frames over an Iub interface (an interface between the node B and the serving radio network controller (SRNC)) and an Iur interface (an interface between the SRNC and the control RNC). When a media access control-improved protocol data unit (MAC-i PDU) or a media access control-enhanced protocol data unit (MAC-e PDU) is received, this protocol data unit is de-multiplexed into media access control data streams (MAC-d streams), then these MAC-d streams are transmitted in one time on separate transport bearers by using the E-DCH uplink data frame type 1 or the E-DCH uplink data frame type 2.
The SRNC receives the E-DCH data frames, decodes the FSN of the data frames in the frame header of this data frame and observes the transmission network layer data delivery condition in a single carrier, such as whether there exists the loss of the E-DCH frame protocol data frame. Frequent disordering delivery will cause the congestion of the transmission network layer, and it affects the execution of the whole system.
With the development of technologies, it is desired that the dual-carrier technology (this technology enables a terminal to transmit data on two carriers, thus enabling the multiplexing of the uplink data rate) to be introduced into the existing system, and the industry has reached an consensus that the data streams based on two carriers should be combined to be executed in the SRNC. If the current E-DCH data frame is used, it will cause the following problems:
Node B receives the MAC-es PDU or MAC-is PDU on two carriers from a Uu port to the Iub port. However, the E-DCH frame protocol data frame in the prior art is directed to the MAC-es PDU or MAC-is PDU on one carrier. When bearing the MAC-es PDU or MAC-is PDU on two carriers, the carrier characteristic of the data stream needs to be exhibited so that the SRNC can obtain the data stream based on carrier characteristic to perform the function control regarding carrier characteristic better. Thus, it is unable to use the E-DCH frame protocol data frame in the prior art. If the node B receives the MAC-e PDU or the MAC-i PDU on two carriers and there enters one E-DCH protocol data frame, that is, the MAC-e PDU or the MAC-i PDU on these two carriers uses the same FSN, then significant modification must be made to the current E-DCH frame protocol data frame. Therefore, this method is undesirable.
Furthermore, the outer loop power control (OLPC) is calculated on the basis of the retransmission data of HARQ of the frame header of the E-DCH frame protocol data frame. If the MAC-e PDU or the MAC-i PDU on two carriers uses the same FSN, then the current E-DCH frame protocol data frame is unable to indicate which carrier information field does the data stream belong to, and the SRNC is also unable to know which carrier does the corresponding MAC-e PDU or MAC-i PDU transmit on. Thus it is unable to perform OLPC.
Consequently, on the basis that the dual-carrier data is not transmitted in the same frame protocol data frame, the present invention provides a method for setting and acquiring a frame sequence number of the enhanced-dedicated transport channel frame protocol. This method can be used in the E-DCH data frame transmission process between an IUb (an interface between the node B and a serving radio network controller (SNRC)) and an Iur port (an interface between the SRNC and the control RNC) which use the high speed packet access technology to transmit data on dual-carrier in a radio communication system. This method is used for setting and acquiring FSN based on the carrier, and for giving the SRNC a better angle to observe the transmission network layer data delivery status in dual-carrier situation so as to detect the problem of the protocol frame data frame loss.
For the problem that if the MAC-e PDU or the MAC-i PDU on two carriers uses the same FSN, then the E-DCH frame protocol data frame is unable to indicate the data stream belongs to which carrier information field and the SRNC is also unable to know the delivery of the corresponding MAC-e PDU or MAC-i PDU is on which carrier and thus unable to perform OLPC, no effective solution is proposed in the related art.